1. Field of the Invention
The present invention relates generally to a keypad for inputting information including characters and digits in a terminal, and in particular, to a wide keypad and a wide keypad mounting structure that increase a touching area for convenient key pressing and minimize static electricity introduced into the keypad.
2. Description of the Related Art
A portable terminal is a mobile station that provides radio communication services to a user by radio communication with a base station. Aside from transmission of voice or pictures, this terminal additionally provides radio communication services such as E-mail or chatting. Commonly, terminals are classified into a bar type, a flip type, and a folder type according to their outer appearances. The terminal is usually comprised of a data input device, an LCD for displaying input data, a voice transmitter/receiver, and an antenna device. A typical terminal is illustrated in FIG. 1. Referring to FIG. 1, the terminal includes a main body 10. On the main body 10 are provided an antenna device 11, an incoming call lamp 12 for visually indicating the reception of a call, an earpiece 13 as a voice receiver, an LCD 14 for displaying input data, a keypad 15 having a plurality of keys for entering information of characters and digits, and a microphone 16 as a voice transmitter.
As shown in FIG. 2, the data input device includes the keypad 15 mounted in an upper casing frame 101 of the main body 10. The keypad 15 has a plurality of keys 150, a sheet portion 151 for integrally connecting the keys 150, contact point protrusions 152 protruding from the lower surface of the sheet portion 151, and engaging portions 153 for restricting the upward movement of the keys 150. This keypad 15 is fabricated by film forming. The ends 150a of the keys 150 are even with or higher than the surface 101a of the upper casing frame 101. As many holes 101b as there are keys 150 are formed in the upper casing frame to fix the keys 150.
A user presses the top ends 150a of keys 150 to enter data. Metal domes, carbon contact points, and a PCB (Printed Circuit Board) are located under the contact point protrusions 152, which are well known and thus will not be described herein.
Currently, terminals are being developed toward small size, lightweight, and improved portability. However, the size of keys is an obstacle to miniaturization of terminals. Though the keys of a keypad should be scaled down in size to miniaturize a terminal, keys that are too small cause a user inconvenience in key pressing. On the other hand, enlarged keys will render data entry convenient but increase the main body of the terminal. Furthermore, when static electricity is introduced through holes into which the keys are inserted in the frame, the conventional terminal encounters the problem of ESD (ElectroStatic Discharge).